1. Field of the Invention
This invention generally relates to a tension applying device. More specifically, the present invention relates to a bicycle chain tensioner for applying tension to a bicycle chain.
2. Background Information
In a bicycle, a chain typically runs between a front sprocket and a rear sprocket. Over time, the chain is gradually stretched with use and may fall off the sprockets. In order to prevent this from happening, a mechanism for applying tension to the chain is often used. In some bicycles, a rear derailleur is used as a shifting device to shift gears. The typical rear derailleur inherently includes a chain tensioning function. However, on the other hand, when an internal shift hub or the like is used to shift gears, there is no chain tension applying function provided by the shifting device. In such a case, a chain tension applying device is added to the bicycle for applying tension to the chain.
A conventionally known chain tension applying device is pivotally mounted to the bicycle with a movable arm supporting a tension sprocket at its free end. The chain tension applying device also includes a coil spring that biases the tension sprocket into engagement with the chain.